The focus of this laboratory has been the MHC class I molecule, classically considered a molecular heterodimer consisting of a 46 kd polymorphic heavy chain, exemplified by the murine H-2K, D, and L molecules (analogous to the human HLA-A, -B, and -C molecules), that is non-covalently assembled with the 12 kd monomorphic light chain, beta2-microglobulin. Our objectives in this project have been to develop an in vitro system for examining early events in the folding and assembly of the MHC molecules.